Change samplingTime Parameter used for FMU Generation into uppercase version to handle the new naming convention warning for it

The FMU Generation in AF3 needs a value for the sampling time. Currently, it looks for a function in the data dictionary of an AF3 model with the name "samplingTime". However, such functions will now always trigger a naming warning, because it is a constant and should therefore be uppercase.

Goal: it should be possible to have a function called "SAMPLING_TIME" in the data dictionary that is used from now on instead of the prior "samplingTime".

Testing:

1. Create AF3 Project
2. Create Data Dictionary
3. Create Component Architecture with one Component with a State Automaton (everything standard/dummy)
4. Generate Task Architecture and Allocations from this Component
5. Generate FMUs for the Component->Task Allocation
6. Observe: Since there is now SAMPLING_TIME function yet, it tells you that in a wizard (and tells you the right name: SAMPLING_TIME() and not anymore samplingTime())
7. Now go into the Data Dictionary and create a SAMPLING_TIME function with a constant return
8. Redo step 5 and observe that now it detects the new (correctly named) function
9. Optional: do it with samplingTime() instead of SAMPLING_TIME() and observe that it does not work anymore